Since 70's, researchers have paid much more attention to studies on algal organisms, especially on blue-green algae. These studies are mainly concentrated on nutritional values and toxicity of the organisms. Of these, spirulina has been considered to be an excellent food resource of human in the future as early as in the Food and Agricultural Organization of the United Nations Conference held in 1974.
The properties of various extracts of algal organisms have been studied since 80's to see whether extracts of algal organisms can be used as potential pharmaceuticals. Of the studies, extracts of blue-green algae, in particular extracts of spirulina have been considered great significance.
Japanese patent application 58-128322 discloses a proteoglycan extracted from microalgae and spirulina inhibiting the growth of leukemia cells. However, no other activities of such a proteoglycan have been disclosed in this application. Although a process for extraction of the proteoglycan from spirulina disclosed therein, the process fails to involve the step of breaking the cellular wall of spirulina. Therefore, the process in this Japanese patent application is expected to be only applied in the laboratory, rather than in the industry with a large scale.
This invention is brought forward based on the inventors' studies on the extraction of proteoglycan of algae and therapeutic activities of the proteoglycan extract of algae.